You open your door and there, sitting on your welcome mat, is a clearly marked package from Amazon. Thing is, you didn't order anything from them, and upon closer inspection, it's apparent this delivery isn't for you. What should you do?
Simple delivery mistakes happen all the time. If it's a simple case of wrong address/correct street and you know for whom the package is intended (like a neighbour), you can walk it over to their place. If it's small enough, place it in their mailbox. If not, give a knock on their door and hand it off. Otherwise, just set it down in front of their door, with the shipping label facing up so it's clearly visible.
If it's somehow addressed to you, well, Amazon gave you a present. Kind of. According to the ACCC, you don't have to pay for any merchandise mailed to you that you did not order. That goes for Amazon or any other retailer who ships goods, and includes any incorrect items mailed to your address, even if the package is correctly addressed to you. More likely than not, Amazon will tell you to keep the item if you reach out to customer service.
OK, but say the item isn't something you want, or the talking cartoon cricket on your shoulder won't let you keep it. In that case, you can contact Amazon and offer to return the merchandise. Just make sure Amazon is the one who pays for all aspects of the return shipping - it's illegal for them not to. Then they will have one month for them to pick up the item and have it returned, and you shouldn't have to pay a cent for any of it.
If you don't get in touch with them, companies have three months to try and recover items sent by mistake and you can't unreasonably refuse their attempts to recover it. You're even liable for any intentional damage so don't give the mystery package to your dog to play with.
If this has happened to you multiple times, and the name on all of the packages is the same, it may be a case of a previous tenant using their old default Amazon shipping address. Feel free to reach out to Australia Post to let them know that person doesn't live there anymore. There's not much else you can do.